1. Field of the Invention
The present invention relates to a fuel cut off valve mounted on an upper wall of a fuel tank to open and close a connection conduit, which connects the inside of the fuel tank with the outside.
2. Description of the Related Art
A well known fuel cut off valve is described in JP-A-7-293,384 and U.S. Pat. No. 5,535,772. The valve comprises two-stage tank fill control valve that has the function of preventing overfill and blowback from filling ports. The valve comprises a bottom valve chamber, a middle valve chamber, and an upper valve chamber, which are disposed from the bottom to the upper portion within a casing, a lower float that is housed within the bottom valve chamber and an upper float that is housed within the upper valve chamber. In structure of the fuel cut of valve, overfilling fuel and fuel blowback from the filling port are prevented through the lower float and the upper float rising and falling sequentially.
While in recent years there have been demands for flattening the fuel cut off valves, accompanying flattened fuel tanks, the conventional valve requires a middle chamber between the upper chamber and the bottom chamber and thus the shape of the fuel cut off valve is large in the vertical direction, making it incompatible with the demands for flattened fuel tanks.
Furthermore, another known conventional valve is described in JP-A-2002-285929. The valve comprises two lower chambers disposed in the horizontal direction, and upper chambers that are disposed continuous with each of the lower chambers above each of these lower chambers, a float housed in each of the lower chambers. The valve is structured to perform the actions described above through the rising and falling of each of the floats depending on the fuel level. However, even in this other conventional valve, the upper chamber is disposed above each of the lower chambers, and thus there is the same problem as the valve descried above.